Side airbag devices are used which, during a side collision of a vehicle or the like, expands an airbag beside an occupant sitting in a seat and deploys the airbag toward the front of the vehicle.
Such side airbag devices include a proposed side airbag device which is designed to improve deployment characteristics of a side airbag by providing a roll-shaped gathering part and a guiding part positioned along both sides of the gathering part when folding the airbag (for example, refer to Japanese Patent Application Laid-open No. 2004-203272).
In addition, a side airbag device is proposed in which, in order to avoid a situation where an airbag rear part and an airbag front part do not deploy and expand appropriately during deployment of an airbag, a partition which divides the airbag into a rear chamber and a front chamber is provided with a communication path which communicates both chambers (for example, refer to Japanese Patent Application Laid-open No. 2013-82435).